Method and device for bonding the sealing flap of a hinge-cover folding box



Sept- 1969 w. H. MAHNCKE 3,465,490

METHOD AND DEVICE FOR BONDING THE SEALING Filed July 6, 1967 I N VEN TOR. William h. Ma/mcke Sept. 9, 1969 w. H. MAHNCKE 3,465,490

METHOD AND DEVICE FOR BONDING THE SEALING FLAP OF A HINGE-COVER FOLDING BOX 4 Sheets-Sheet 4 Filed July 6, 196

44 40 45 4/ 46 47 45 v 49 I; r

Fig. 5

INVENTOR. William H. Ma/mcke 4; A TTOR/VEV United States Patent 3,465,490 METHOD AND DEVICE FOR BONDING THE SEALING FLAP OF A HINGE-COVER FOLD- ING BOX William H. Mahncke, San Mateo, Calif., assignor to Kliklok Corporation, New York, N.Y., a corporation of Delaware Filed July 6, 1967, Ser. No. 651,406 Int. Cl. B65b 7/20, 51/20 U.S. Cl. 53-38 Claims ABSTRACT OF THE DISCLOSURE The present improvements prevent bowing-in of the box body wall panel over which a hinge cover sealing flap is folded and to which it is to be adhesively bonded. This is accomplished by drawing the panel outwardly by suction applied to the outside surface of the wall panel. Suction is also applied to the sealing flap. Flap and panel remain flat and the compression force on the bonding area is the result of the applied suction.

BACKGROUND OF THE INVENTION Folding boxes of relatively large size and of relatively thin caliper paperboard present problems in the adhesive bonding of the cover sealing flap which is folded over a wall panel of the box body.

The box body wall tends to cave in and bow inwardly of the box, if sealing pressure is exerted on the sealing flap, and this tendency is aggravated, if the box contents by reason of shape or lack of rigidity cannot be relied on to back up the panel to counteract the sealing pressure. The problem is particularly acute in the packaging of bakery products, as the boxes are relatively large, thin walled and sanitary regulations require a tight seal.

The problem is overcome by dispensing with the conventional exertion of an inwardly directed sealing force on the flap, which is the primary cause of the caving in of the wall panel and by applying, instead, a sealing force directed from the inside out by suction applied to the outside of the box to draw the panel against the flap, while supporting the flap against outward bowing by a lateral guide element, rail or the like, which may be separated from, or combined with, the suction applying means.

' Prior art It is known in this connection to employ suction in the closing and bonding of so-called four-flap end closure boxes in which two smaller end flaps are infolded first, and in which a main inner end flap is folded thereover to be bonded to the smaller first folded flaps. The small flaps offer only limited resistance when sealing pressure is exerted on the inner end flap. In order to increase the flap resistance, it is known to provide large apertures in the inner end flap, to apply suction through the apertures, as a result of which the small flaps are drawn up tightly against the underside of the main inner end flap. A reliable bond is thus formed, and at the same time the apertures are closed by the valve action of the smaller flaps so that the contents are not sucked out. The outer main end flap is finally folded over and bonded to the inner main fiap in a conventional manner involving the exertion of sealing pressure directed towards the inside of the box and sustained by the previously formed three-flap base.

The objects, features and advantages of this invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, a manner in which the invention may be carried out. The invention also resides in certain new and original features of construction and combinaice tion of elements, as well as steps and sequences of steps hereinafter set forth and claimed.

Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and a manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying drawings showing a portion of an otherwise conventional box closing machine modified by installation of the elements necessary to practice the present invention. More particularly, the machine was originally built to comprise a box conveyor and means for activating, by a hot air blast, preapplied thermoplastic adhesive on the box body wall and the box cover flap followed by means for downfolding the flap. For the purpose of practicing the present invention there was added what might be called a compression-by-suction section, and temporary means were used for adapting a wide box track to narrower boxes, resulting in a device capable of sealing boxes at normal production speeds.

Brief description of the drawings FIG. 1 is a perspective view of the adhesive activating and sealing section of the machine;

FIG. 2 is a perspective vie-w of the machine showing a box passing through the adhesive activating section and entering the suction section is which the areas to be bonded are pressed together;

FIG. 3 is a perspective view of the machine of FIG. 2 at a later phase at which the box leaves the suction section;

FIG. 4 is a perspective view of a portion of the box shown in FIGS. 1 to 3, illustrating details of the closure; and

FIG. 5 is a section on line 55 in FIG. 3 of a suction box.

In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.

The drawings accompanying and forming part of this specification disclose certain specific details of construction for the purpose of explanation of broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the principles of the invention, and that the invention may be incorporated in, and practiced by, other structural forms than shown.

DESCRIPTION OF A REPRESENTATIVE EMBODIMENT Referring to FIGS. 1 to 3, the closing and sealing or bonding machine comprises a box track generally designated 11 (FIG. 3) on which boxes B may move, supported by rails 12 set on edge, the boxes being advanced by endless conveyors fitted with lugs which move the boxes toward the observer.

There are three conveyor chains of which chains 13 and 14 form an outer pair and a central chain 15 is disposed between the pair 13, 14. Chain 15 is hidden from view in FIG. 3, but is visible in FIG. 1.

Pusher lugs 16, 17 on chains 13, 14, respectively, serve to propel the boxes along the track and represent the rear end of box compartments, the front end of which is formed by a leading lug 18 on the central chain 15.

In operation all three chains 13, 14 and 15 are driven at the same speed. The chain 15, however, is adjustable with respect to the chains 13 and 14 so as to permit the distance between lugs 16, 17 and lug 18 to be lengthened or shortened in order to accommodate longer or shorter boxes. Such adjustment is well known. The illustrated machine was adjusted to provide compartments of the proper length for the boxes B.

It is readily seen, however, that the width of the illustrated machine is excessive for the boxes. In order to take up excess space, spacer blocks 19 were used so as to permit the boxes B which were available for test purposes to be run on the illustrated machine, which also happened to be available for the test.

The boxes B are specifically designed for the packaging of doughnuts and are of a known design. It will therefore suffice to describe only those box elements which are relevant for the description of the present method and machine operation.

Referring more particularly to FIGS. 3 and 4, the box B comprises a box cover panel 20 having a cover front flap 21 and cover end flaps 22 thereon. The end flaps 22 have corner glue tabs 23 thereon which are to be bonded to the underside of the front flap 21.

The cover panel 20 is folded over the box body which comprises a body front panel 24 and body end panels 25.

The cover front flap 21 comprises a rip-out portion 26 defined by interrupted cuts 27, 28 forming boundaries of Weakness along which the tab may be ripped from the remainder of the front flap when grasped near its edge 29 and pulled to the right. In order to expose this edge 29 a wedge-shaped portion 30 is notched out of the flap 21. The rip tab 26 is bonded to the body front panel by adhesive applied to it or to the front of the panel 24, or to both.

Conventional liquid adhesive may be used for this purpose, but higher production rates are attainable by use of a preapplied thermoplastic adhesive A within the areas marked by stippling or dotting. Such thermoplastic adhesive requires activation in order to render it tacky. This is done on the sealing machine by application of a blast of hot air to the flap 21 and the panel 24.

When the cover front flap 21 is folded down its rip tab portion 26 comes to lie on an elongated peel area 31 formed within the panel by a surface cut 32 which extends partially into, but not through, the board. When the sealed box is opened by ripping out the rip tab 26, thereby severing it from the front flap 21 along lines 27 and 28, the adhesive bond between rip tab 27 and the front panel 24 causes the board to peel within the area 31 circumscribed by the surface cut 32.

Simultaneously with the bonding of the rip tab 26 to the body panel 24 the ends of the front flap 21 are bonded to the corner flaps 23 by adhesive applied at the end areas or to the flaps 23, or to both.

It may be mentioned the preapplication of thermoplastic adhesive to predetermined areas may be omitted in the event the box board is already coated with a thermoplastic film in order to make the board resistant to the absorption of grease, or to reduce the moisture vapor transmission or for other reasons. Although such coating films are extremely thin, they are suitable for heat bonding by application of the proper amount of heat within a very brief period of time which, in turn, permits the box to be advanced at a very rapid rate. This is described in detail in the patents to Hittenberger et al. No. 3,416,411 dated Dec. 17, 1968 and No. 3,340,777 dated Sept. 12, 1967.

Returning to FIG. 1, a box B is approaching from the left. Its cover panel 20 is folded down fully over the box body and its cover front flap 21 forms an acute angle, in end view, with the front of the box. The cover front flap is kept in the downwardly inclined position by a sword plate 33 over which it is folded and held by a round folding bar 34.

The box approaches a hot air discharge head 35 having a series of nozzles 36 on the side facing the observer for discharging hot air against the body front panel 24 and the corner flaps 23 folded thereover. A similar series of nozzles 37 are on the reverse side for applying hot air to the underside of the flap 21. The nozzles 37 are visible in FIG. 2 just below the notched-out portion of the cover front flap 21.

Immediately after heating the front panel is folded down by means of a plow or rail 38 visible in FIGS. 1 and 2. FIG. 1 also shows the heating unit 39 on the end of which the discharge head 35 is mounted and which is supplied with compressed air by a suitable blower (not shown).

In order to complete the bond it is necessary to exert compression (in box makers terminology) between the front flap 21 and the front panel 24.

According to the invention suction is applied to the box body front panel 24 in order to prevent it from bowing in. For this purpose one, or preferably several suction boxes in series, are arranged along the box track. Two such suction boxes 40 are shown in the drawings, each having a hose nipple 41 from which a hose 42 extends to a source of vacuum seen in FIG. 1 behind the machine in the form of a multistage turbine 43.

The suction boxes 40 have face plates 44 on them which are contoured to provide upper, central and lower contact surfaces on rails 45 leaving recessed areas or grooves 46 therebetween from which air is withdrawn through passages 47 into the interior of the suction boxes 40 which forms a plenum chamber 48.

It is apparent from FIGS. 3 and 5 that the central contact surface contacts the front flap 21 adjacent its terminal edge 49 so that suction is applied to the flap 21 in an area immediately above the edge while suction is being applied to the front panel immediately below the edge.

Application of suction to the front panel 24 draws it against the face plate 44, thereby applying a sealing force F directed from the inside of the box against the face plate 44 and suction box 40 which act as a guide element alongside the box track.

Application of suction to the front flap 21 has the effect of flattening the flaps out, in the event the flap tends to curl as a result of the application of heat.

In the position in which the box is shown in FIG. 3 the surface grooves of the face plate 44 of the far suction box 40 are being progressively exposed to the atmosphere leading to a reduction of the suction. In order to avoid a consequent loss of vacuum near the leading portion of the box, more than one suction box is employed. Manifestly any loss of vacuum at the far suction box has no adverse effect on the near box. For this reason each box is given its own suction hose and the several hoses 42 are manifolded only at a point close to the vacuum pump or turbine 43. It is therefore preferred to employ suction boxes shorter than the length of the folding boxes to be sealed.

When the box passes beyond the last suction box, it is securely sealed. The amount of heat absorbed by the board is small because of the very brief exposure to heat. In fact, the application of heat is so brief that the heat has no time to penetrate the board before the two surfaces are brought together. The bond then cools quickly, firstly, by absorption into the board and, secondly, by the cooling action of the air which sweeps past the board as atmospheric air enters the grooves 46. As is clearly seen from FIG. 3, this happens only after the bonding areas have been subject to compression-by-suction.

It is preferred in this connection to arrange the passages 47 near or at the ends of the grooves 46 at which the box departs.

What is claimed is:

1. In the method of bonding the sealing flap of a folding box hinge cover to a wall panel of the box body involving the folding of the flap over the panel into face-toface contact to cause the flap surface to adhere to the panel surface by means of an adhesive coating on at least one of the two surfaces while the box is being advanced in a direction parallel to the hinge line of the flap, and involving the application of suction to the panel within an area adjacent the terminal edge of the fiap to draw the panel against a lateral guide element extending in the direction substantially parallel to the direction of box travel, the step of simultaneously applying suction to the flap within an area adjacent its terminal edge to draw the flap against the lateral guide element so as to maintain it free from curling during the bonding.

2. A device for bonding a sealing flap of a folding box cover to a box body wall panel over which the flap is folded, by means of adhesive preapplied to at least one of the two surfaces to be bonded, the device comprising means for advancing the box in a direction of the flap fold line, lateral guide means extending along the path of the box in a position adjacent the cover flap and said wall panel, and suction means for drawing said wall panel towards the guide means at an area adjacent the terminal edge of the flap, characterized in that the suction means is so disposed as to simultaneously apply suction to the sealing flap in an area adjacent its terminal flap edge to flatten the flap edge against said guide means during bonding.

3. A device according to claim 3 in which the lateral guide means comprises three vertically spaced horizontally extending contact surfaces in a position in which the central surface contacts the flap adjacent its edge, the lower surface contacts the wall panel below said edge, and the upper surface engages the sealing flap above said central surface, and in which air is being withdrawn from between said contact surfaces.

4. A device for bonding a sealing flap of a folding box cover to a box body wall panel over which the flap is folded, by means of adhesive preapplied to at least one of the two surfaces to be bonded, the device comprising, in combination, means for advancing the box in the direction of the flap fold line; means for downfolding the sealing flap into a position overlying the box body panel; a suction box alongside the box path and downstream with respect to said downfolding means, said suction box comprising three vertically spaced horizontally extending contact strips positioned to contact the box above, adjacent, and below the terminal edge of the sealing flap, respectively, and a plenum chamber in communication with the spaces between the contact strips; and means for maintaining the plenum chamber at subatmospheric pressure. 5. A device according to claim 4 in which two suction boxes are arranged end-to-end, each suction box being shorter than the boxes whose flaps are to be bonded.

References Cited UNITED STATES PATENTS 2,435,878 2/1948 Dunning 53374 X 2,485,040 10/1949 Cupo 53-387 X 3,107,469 10/1963 Mosse et a1 53--374 X TRAVIS S. McGEHEE, Primary Examiner US. Cl. X.R. 53-376 

